U.S. Pat. No. 6,645,177 to Shearn, which is incorporated herein by reference in its entirety, discloses a syringe driver system with a threaded lead screw shaft and a plunger. The threaded features of Shearn relate to controlled dosing of a substance from the syringe. Shearn fails to provide a threaded shaft or plunger assembly with enhanced pull out resistance.
U.S. Pat. No. 7,645,267 to Vetter et al., which is incorporated herein by reference in its entirety, provides a prefilled syringe with a plunger provided in the barrel and a thread system cooperating with the plunger rod and the finger support. The thread system of Vetter et al., however, fails to disclose various locking and enhanced pull out features.
U.S. Pat. No. 8,002,754 to Kawamura et al., which is incorporated herein by reference in its entirety, provides a plunger rod with a threaded portion to permit attachment between the rod and a piston. Kawamura et al. fails to disclose, however, locking features associated with the threaded portion to secure the threaded portion and a stopper or piston.